performance and acceptability of vss-r

Conditions: Refractive Error

Summary: the results of this trial will demonstrate that avss software performs as intended and is acceptable in a clinical setting.

lasik treatment across the range of myopia with or without astigmatism, hyperopia with or without astigmatism, and mixed astigmatism.

Eligibility criteria:
inclusion criteria: * male or female, of any race, and at least 21 years old at the time of the pre-operative examination and signing the consent form. * the refractive error, based on manifest refraction at the spectacle plane, of: mrse up to -15.00 d with manifest cylinder between 0.00 and -6.00 d; mrse up to +7.00 d, with manifest cylinder between 0.00 and 6.00 d; or manifest cylinder (from 1.0 to 6.0 d) greater than the magnitude of sphere, and the manifest cylinder and sphere have opposite signs. * bscva of 20/20 or better. * ucva of 20/40 or worse. * manifest refraction sphere within ± 0.75 d of cycloplegic refraction sphere (at the same vertex distance). * anticipated post-operative stromal bed thickness of at least 250 microns, based on pre-operative central corneal pachymetry minus the maximum treatment depth to be ablated and the intended flap thickness, and confirmed by intra-operative central corneal pachymetry. * anticipated post-operative keratometry value (based on pre-operative manifest refraction and keratometry) that is appropriate. * a stable refractive error, based on an exam (or prescription) at least 12 months prior to the pre-operative examination and as compared to the pre-operative manifest refraction * subjects who have worn a contact lens in the operative eye must discontinue lens wear at least three (3) consecutive weeks prior to the pre-operative examination. if, upon review of pre-operative measurements, the investigator determines that the corneal topography is within normal limits, surgery may be scheduled (within 60 days), with no contact lens wear permitted prior to the surgery. * willing and capable of returning for follow-up examinations for the duration of the study (6 months). exclusion criteria: * women who are pregnant, breast-feeding, or intend to become pregnant over the course of the study, as determined by verbal inquiry. * concurrent use of topical or systemic medications that may impair healing, including but not limited to: antimetabolites, isotretinoin (accutane®) within 6 months of treatment, and amiodarone hydrochloride (cordarone®) within 12 months of treatment. * history of any of the following medical conditions, or any other condition that could affect wound healing: collagen vascular disease, autoimmune disease, immunodeficiency diseases, ocular herpes zoster or herpes simplex, endocrine disorders (including, but not limited to unstable thyroid disorders and diabetes), lupus, and rheumatoid arthritis. * subjects with a cardiac pacemaker or implanted defibrillator. * history of prior intraocular or corneal surgery (including cataract extraction), active ophthalmic disease or abnormality (including, but not limited to, symptomatic blepharitis, recurrent corneal erosion, dry eye syndrome, neovascularization \> 1mm from limbus), retinal detachment/repair, clinically significant lens opacity, clinical evidence of trauma, corneal opacity within the central 9 mm, at risk for developing strabismus, or with evidence of glaucoma or propensity for narrow angle glaucoma. * evidence of keratoconus, corneal dystrophy or irregularity, or abnormal videokeratography. * known sensitivity or inappropriate responsiveness to any of the medications used in the post-operative course. * subjects with one eye that does not meet all inclusion criteria and does not fall within approved indications for treatment using the visx® star s4 ir® excimer laser. * participation in any other clinical study.